从零开始手写mmo游戏从框架到爆炸（七）— 消息封装

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    上一篇，我们初步把消息handler 注册到了服务中，在进行后续工作之前我们需要再做一些准备工作。

        第一：把之前自己管理的bean放到spring中去管理，后面大部分的bean都通过spring来管理。

        第二：为了方便路由消费，我们要创建一个消息体方便byte字节数组传输。

Spring        

先把spring上下文变量工具整好

SpringContextHelper.java

package com.loveprogrammer.base.factory;import org.springframework.context.ApplicationContext;public class SpringContextHelper {private static ApplicationContext ac;public static void setApplicationContext(ApplicationContext ac) {SpringContextHelper.ac = ac;}public static ApplicationContext getContext() {return ac;}public static Object getBean(String name) {return ac.getBean(name);}public static Object getBean(Class clazz) {return ac.getBean(clazz);}}

CommonBootConfig.java

import com.loveprogrammer.base.factory.SpringContextHelper;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Configuration;@Configuration
public class CommonBootConfig implements ApplicationContextAware {@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {SpringContextHelper.setApplicationContext(applicationContext);}
}

修改 NetworkListener.java

@Component
public class NetworkListener implements INetworkEventListener {

 修改 TcpMessageStringHandler.java

@Component
public class TcpMessageStringHandler extends SimpleChannelInboundHandler<String> {private static final Logger logger = LoggerFactory.getLogger(TcpMessageStringHandler.class);@Autowiredprivate INetworkEventListener listener;//    public TcpMessageStringHandler(INetworkEventListener listener) {
//        this.listener = listener;
//    }

修改TcpServerStringInitializer.java

public class TcpServerStringInitializer extends ChannelInitializer<SocketChannel> {@Overrideprotected void initChannel(SocketChannel ch) {ChannelPipeline pipeline = ch.pipeline();pipeline.addLast("framer",new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));pipeline.addLast("decoder", new StringDecoder());pipeline.addLast("encoder", new StringEncoder());TcpMessageStringHandler handler = (TcpMessageStringHandler) SpringContextHelper.getBean(TcpMessageStringHandler.class);pipeline.addLast(handler);}}

 消息封装

创建一个类 StringMessage

package com.loveprogrammer.pojo;import com.alibaba.fastjson2.JSON;/*** @ClassName StringMessage* @Description string类型的请求的请求体* @Author admin* @Date 2024/1/31 10:35* @Version 1.0*/
public class StringMessage {/****         topicId 路由主键对应class*         tagId 路由副健，对应method*         statusC内容的长ode主要是返回内容是告诉客户端消息的状态，成功为1，其他不同的错误使用不同的错误码*         length是度，内容的长度是不可控制的，所以使用一个长度进行定义*         body是具体的内容*/private int topicId;private int tagId;private int statusCode;private int length;private String body;public StringMessage() {}//    public StringMessage(short messageId) {
//        this.messageId = messageId;
//    }public static StringMessage create(int topicId,int tagId) {StringMessage stringMessage = new StringMessage();stringMessage.setTopicId(topicId);stringMessage.setTagId(tagId);return stringMessage;}public static StringMessage create(String origin) {StringMessage stringMessage = JSON.parseObject(origin, StringMessage.class);return stringMessage;}public static StringMessage create(int length, int topicId,int tagId , int statusCode, String content) {return new StringMessage(length, topicId, tagId, statusCode, content);}private StringMessage(int length, int topicId,int tagId, int statusCode, String body) {this.length = length;this.topicId = topicId;this.tagId = tagId;this.statusCode = statusCode;this.body = body;}public int getTopicId() {return topicId;}public void setTopicId(int topicId) {this.topicId = topicId;}public int getTagId() {return tagId;}public void setTagId(int tagId) {this.tagId = tagId;}public int getStatusCode() {return statusCode;}public void setStatusCode(int statusCode) {this.statusCode = statusCode;}public int getLength() {return length;}public void setLength(int length) {this.length = length;}public String getBody() {return body;}public void setBody(String body) {this.body = body;}@Overridepublic String toString() {return "StringMessage{" + "messageId=" + topicId + ", statusCode=" + statusCode + ", length=" + length+ ", body='" + body + '\'' + '}';}
}

  创建两个编解码类 

  MessageDecoder.java

package com.loveprogrammer.codec;import com.loveprogrammer.constants.ConstantValue;
import com.loveprogrammer.pojo.StringMessage;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;/*** @ClassName MessageDecoder* @Description 消息解码器* @Author admin* @Date 2024/1/31 10:43* @Version 1.0*/
public class MessageDecoder extends LengthFieldBasedFrameDecoder {//判断传送客户端传送过来的数据是否按照协议传输，头部信息的大小应该是 int+int+int = 4+4+4 = 12private static final int HEADER_SIZE = 12;private int topicId;private int tagId;private int statusCode;private int length;private String body;/***** @param maxFrameLength 解码时，处理每个帧数据的最大长度* @param lengthFieldOffset 该帧数据中，存放该帧数据的长度的数据的起始位置* @param lengthFieldLength 记录该帧数据长度的字段本身的长度* @param lengthAdjustment 修改帧数据长度字段中定义的值，可以为负数* @param initialBytesToStrip 解析的时候需要跳过的字节数* @param failFast 为true，当frame长度超过maxFrameLength时立即报TooLongFrameException异常，为false，读取完整个帧再报异常*/public MessageDecoder(int maxFrameLength, int lengthFieldOffset, int lengthFieldLength, int lengthAdjustment, int initialBytesToStrip, boolean failFast) {super(maxFrameLength, lengthFieldOffset, lengthFieldLength, lengthAdjustment, initialBytesToStrip, failFast);}@Overrideprotected Object decode(ChannelHandlerContext ctx, ByteBuf in) throws Exception {if(in == null){return null;}if(in.readableBytes() < HEADER_SIZE) {throw new Exception("可读信息段比头部信息都小");}// 注意在读的过程中，readIndex的指针也在移动topicId = in.readInt();tagId = in.readInt();statusCode = in.readInt();length = in.readInt();if(in.readableBytes() < length) {throw new Exception("body获取长度" + length + ",实际长度没有达到");}ByteBuf buf = in.readBytes(length);byte[] req = new byte[buf.readableBytes()];buf.readBytes(req);body = new String(req, ConstantValue.PROJECT_CHARSET);StringMessage stringMessage = StringMessage.create(length, topicId, tagId, statusCode, body);return stringMessage;}
}

MessageEncoder.java

package com.loveprogrammer.codec;import com.loveprogrammer.constants.ConstantValue;
import com.loveprogrammer.pojo.StringMessage;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;import java.nio.charset.Charset;/*** @ClassName MessageEncoder* @Description 消息编码器* @Author admin* @Date 2024/1/31 10:40* @Version 1.0*/
public class MessageEncoder extends MessageToByteEncoder<StringMessage> {@Overrideprotected void encode(ChannelHandlerContext ctx, StringMessage msg, ByteBuf out) throws Exception {if(null == msg) {throw new Exception("msg is null");}String body = msg.getBody();byte[] bodyBytes = body.getBytes(Charset.forName(ConstantValue.PROJECT_CHARSET));out.writeInt(msg.getTopicId());out.writeInt(msg.getTagId());out.writeInt(msg.getStatusCode());out.writeInt(bodyBytes.length);out.writeBytes(bodyBytes);}
}

 下一章我们来实现byte数组传输数据

上一篇：从零开始手写mmo游戏从框架到爆炸（六）— 消息处理工厂-CSDN博客

全部源码详见：

gitee : eternity-online: 多人在线mmo游戏 - Gitee.com

分支：step-06